Temperature is one of the factors that most affects how comfortable we are at night. A room that is too warm, a mattress that holds on to heat or moisture that is slow to disperse is all it takes to find ourselves shifting position, throwing off the covers or waking up feeling overheated. When it comes to thermal comfort, however, the temperature of the room is only part of the picture. What we sleep on also helps to shape the microclimate that forms around the body.
What happens to body temperature during the night
The body does not keep the same temperature across the twenty-four hours. As sleep approaches, core body temperature physiologically tends to fall, while the body carries on producing heat and releasing it into its surroundings.
The mattress, bed linen and fabrics are therefore in contact with a body that, for several hours, generates heat and gives off moisture. If they hinder its escape, the microclimate of the bed can gradually become warmer and more humid.
This is why the feeling of “sleeping cool” does not necessarily depend on a surface that feels cold at first touch. True thermal comfort lies in the ability of the bed system to manage heat over the whole night.
Not all materials behave the same way
What a mattress is made of has a direct bearing on this balance. Some materials let air pass through more freely, others are able to absorb and release moisture, and others still are designed to help heat dissipate.
Natural fibres such as wool and cotton have traditionally been used for these qualities, among others. Wool in particular can help to manage moisture and the microclimate, while cotton encourages breathability and the passage of air.
But temperature control does not rely solely on natural materials. Applied research in the field of sleep has led to the development of materials and technologies designed specifically to act on body heat.
One example is Technogel, whose three-dimensional gel material is used on the surface of the mattress to help heat disperse and to reduce the build-up of warmth in the areas in contact with the body.
Two different approaches – that of natural fibres and that of technological research – which show how the choice of materials can have a tangible effect on the way temperature is managed.
The mattress has to be considered as a whole
Focusing solely on the outermost material, however, can be misleading. The thermal behaviour of a mattress depends on the interplay of several elements: fillings, internal structure, cover, capacity for ventilation and even the base on which it is used.
Bed linen plays an important part too. Sheets, mattress protector, duvet and pillow all share in the same microclimate and can noticeably change how temperature is perceived.
It is therefore more accurate to speak of a bed system than of any single “cool” material.
A very personal sensation
Finally, there is one aspect that no specification sheet can entirely settle: the perception of temperature varies from person to person. Some people tend to feel warm all year round, some are more troubled by humidity, some look for a cooler surface, while others, on the contrary, prefer a greater sense of warmth and a more enveloping feel.
That is why, when choosing a mattress, talking about your habits and how you feel during the night can be as important as settling on the degree of firmness or the kind of support you want.
Comfort is not only a matter of how a mattress supports the body, but also of the environment it is able to create around that body, all night long.
